Apparatus and method for bending,drawing and burnishing a metal workpiece



A METAL WORKPIECE Filed D60. 13, 1965 5 3 RM A WRO 0/ R; n F M w o n W 5 DM S 8 ER L MM 5 k D0 M/ July 29, 1969 D. 0. DOERR ET AL APPARATUS AND METHOD FOR BENDING DRAWING AND BURNISHING United States Patent US. Cl. 72212 7 Claims ABSTRACT OF THE DISCLOSURE Improved method and apparatus for bending a length of metallic strip into a U-shaped workpiece having leg portions, thereafter drawing the bent shaped workpiece in such a fashion as to burnish these leg portions and then severing the burnished leg portions of the workpiece from each other.

This invention relates to a method and apparatus for forming a given length of metallic strip material such as metallic plate into a pair of plate sections of a predetermined length and gauge and of the desired surface finish on one of the surfaces thereof. More particularly, it is concerned with providing an improved method and apparatus for forming a given length of metallic plate such as aluminum or aluminum alloy plate into two plate sections of a predetermined gauge and length and of the desired surface finish on one of the surfaces of each of the plate sections by bending, drawing burnishing and severing he plate in a unique fashion.

Accordingly, it is the primary purpose of the instant invention to provide an improved method and apparatus for finishing a length of metallic plate such as one made from aluminum or an aluminum alloy wherein the length of plate is bent, drawn, burnished and severed in a unique fashion.

This and other purposes and advantages of the instant invention will become more apparent from a review of the following detailed description when taken in conjunction with the appended drawings, wherein:

FIG. 1 is a perspective view with certain parts broken away and other parts being shown in dotted and solid lines and illustrates a preferred embodiment of an apparatus for carrying out the teachings of the instant invention;

FIG. 2 is an enlarged cross-sectional view generally taken along line 2-2 of FIG. 1, wherein certain parts have been removed or broken away and wherein the ram of the apparatus is shown in a workpiece engaging and Work performing position;

FIG. 3 is a cross-sectional view similar to FIG. 2 and illustrates a further workpiece engaging and work performing position of the ram;

FIG. 4 is an enlarged fragmentary perspective view of a portion of the apparatus of FIG. 1; and

FIG. 5 is an end elevational view of a workpiece produced by the apparatus of FIG. 1 and prior to the Severance thereof into two sections.

With further reference to the drawings, a preferred form of improved apparatus that can be used in carrying out the teachings of the invention generally comprises a frame made up of appropriate plate, channel and rod members welded or otherwise secured together. Mounted upon frame 10 is ram 12 and a cooperating die assembly 14, all of which will be described more fully hereinafter. A suitable control circuit 16 diagrammatically shown in FIG. 1 is used to control the movements of the ram. A relatively "ice fiat workpiece such as made of aluminum or aluminum alloy and of a given length and width is suppplied by appropriate means (not shown) to the uppermost surface of the die assembly 14 in the fashion generally shown by dotted lines in FIG. 1. When the ram 12 has been fully advanced it forms the workpiece in a unique manner into a shape approximating the letter U such as is shown in FIG. 5. The drawn end portions S of the workpiece are of substantially the same gauge and length while the outwardly facing major surfaces of the drawn end portions are burnished to a high polish. During operation of the apparatus, the advancing ram 12 and die assembly 14 cooperate to initially center and bend the workpiece W about a transverse portion thereof. The bent workpiece W as indicated in FIG. 2 is next passed through a forming means within the die assembly 14 to effect a predetermined drawing of the end portion S of the workpiece above the transverse or nose portion N thereof. An advantageous burnishing of the outwardly facing major surfaces on the end portions S of the workpiece takes place simultaneously with the drawing thereof. Although not heretofore mentioned and as will be apparent hereinafter, the workpiece W could be prebent if desired by some other suitable means (not shown) so that the instant apparatus described hereinafter would only effect a drawing and burnishing of the prebent workpiece.

In the aluminum industry the gauge dividing line between sheet and plate stock is A". Metal of a thickness greater than A is ordinarily classified as plate and metal of less than A" down to .006" is ordinarily classified as sheet. Although the instant apparatus and method can be used to finish aluminum and aluminum alloy sheet, it is advantageously used for producing printing plates used in the printing industry. These plates frequently require a high surface finish on one side thereof and they must be made to conform to the exacting requirements on the part of the user. The instant apparatus and method provide a simple and inexpensive way for manufacturing such highly specialized and custom made plate products.

The frame 10 generally comprises an upper and a lower end section interconnected by a series of parallel spaced rod members 18. The upper ends of the rod members 18 are secured to the interconnected open and closed end channel members 20 and 22 forming the upper portion of the frame. The lower portion of the frame 10 includes separate pairs of bar members 24 and 26 and a base plate 28. The longitudinal ends of the bars can be rounded off and they have aligned openings for receiving and anchoring the lower ends of the rods 18 to the frame. The bars 24 and 26 substantially correspond in length to the oppositely disposed channel members 20 and 22. Moreover, the bars 26 are afi'ixed in a suitable manner to the base plate 28. It is further observed here that the bars 26, even though illustrated as partially broken away, are of a sufficient height relative to the die assembly 14 and the base plate 28 so as to provide ample clearance, as will be further apparent hereinafter, for the workpiece during the forming thereof.

Ram 12 is actuated by a fluid actuator 39 rigidly mounted by means of the plates 34 to the upper portion of the framework and intermediate the ends of the channel members 20. The cylindrical housing 32 of the actuator 30 fits within the aligned openings 36 of the plates 34 and is welded to these plates. The plate members 34 are atfixed to frame elements 20 by suitable stud bolts 35. A suitable double acting piston is disposed in housing 32 and a piston rod 38 extending through the rod end of the housing is connected to this piston. The piston rod 38 is rigidly connected in a conventional manner at its forward end to the ram 12.

A suitable fluid control circuit 16 is connected to the actuator 30 for operating the piston in housing 32 and its associated piston rod 38 and the ram 12. This circuit 16 includes a manually or automatically operated control valve 40 connected to a source of fluid under pressure from the reservoir 42 through the medium of a supply conduit 44 having disposed therein an appropriate fluid pump 46. A bypass line 44 passes the fluid back to reservoir 42 when valve 40 is closed. Depending upon the operative position of valve 40, fluid under pressure is directed to branch conduit 48 or 50 for respectively advancing and retracting the ram 12 in the usual manner, branch conduit 48 being connected to the piston side of the housing 32 and branch conduit 50 being connected to the rod end of the housing 32.

The die assembly 14 comprises a series of block members rigidly assembled together in a unique fashion whereby the apparatus can advantageously carry out the teach ings of the instant invention. The series of block members include intermediate block members 54 disposed in parallel spaced relation and held in place by end block members 56. Each end block member 56 is locked at its ends to the associated end poritons of the spacer blocks 54 by suitable cap screws 57 which pass through aligned openings in the block members '54 and 56. Block 54 to which blocks 56 are anchored is sandwiched between upper and lower block elements 56 and 64 and locked thereto by appropriate cap screw fastening elements 58 which fit in openings 59'. It is observed here that the intermediate surface 59 of each end block can be recessed laterally inward into the body of the block 56, as is evident in FIG. 4. The purpose of the recessed surfaces 59 is to assure ample clearance between the rounded edge of the ram 12 and the surfaces 59 as will be further apparent hereinafter. The oppositely facing surfaces 60 of the atfixed and spaced cap members 56 are disposed in planar alignment with the surface 62 on the associated block member 54. The spaced block members 54 are affixed to the top surface of the apertured supporting plate 64 by means of cap screws 65 which pass through respective openings 67 in the plate 64 and into threaded engagement with aligned openings 67 in the block members 54 as shown in FIGS. 2 and 3. The block members '54 affix the die assembly 14 to the plate 64 in such a fashion that the part of the opening through the die assembly 14 defined by the surfaces 60 and 62 of the block and cap members is disposed in alignment with the opening 66 through the plate 64 whereby the aligned openings of the block and cap members 54, 56 and '56 and plate 64 define a common opening 68 therethrough, which permits the passage of the ram 12 with the workpiece W therethrough during the forming thereof as hereinafter described. Although only the transverse dimension of the opening 66' is indicated in FIGS. 2 and 3 to be larger than corresponding dimension of the upper part of the opening in the blocks of the die assembly 14, it is to be understood that the opening 66' in the plate 64 is also larger in its lateral dimension.

The compositely constructed die assembly 14 functions to bend the workpiece W about a transverse portion disposed intermediate its length. The inner surface 60 and the upper surface 70 of each cap member 56' at their lines of intersection are advantageously rounded off in a suitable fashion as best shown in FIGS. 2v and 3 whereby upon the initial stroke advancement of the ram 12, each end portion of the fed workpiece W is readily bent in a predetermined fashion through an acute angle of no more than 90 relative to a transverse intermediate portion of the workpiece so as to form the workpiece into the shape approximating the letter U. After bending of the workpiece W, continued advancement of the ram 12 through the opening 68 of the die assembly 14 effects a reduction in the gauge of the end portions S of the bent workpiece W by drawing and effecting a flow of metal in the portions S" of the workpiece back upon themselvesby passage of the 4 workpiece between rolls 72 located in die assembly 14 and to be described hereinafter.

The axes of the pair of rolls 72 are disposed parallel to the plane of movement of the ram 12 and they are mounted for free rotation in recesses 74 in the blocks 54 by means of journal bearings 75 located in openings in block members 56 which receive the ends 73 of the rolls 72. A pair of backup rolls 76 can be used with each roll 72 and the periphery of the roll 72 is in rolling contact therewith. These backup rolls 76 are located in suitable openings 78 in each of the blocks 74 in such a fashion as to be in bearing contact with rolls 72. When the rolls 72 and 76 are mounted in their respective recesses and openings, as the case may be, each one of a pair of backup rolls 76 is in rolling contact at different points along the roll 72 in the associated block 54. The backup rolls 76 can be reduced at their ends in a manner similar to rolls 72 to facilitate their mounting in the end blocks 56. With both rolls 72 mounted in the die assembly, as aforedescribed, the chordal protruding portions of the rolls 72 cooperate to define a transverse restricted passage within the common die assembly opening 68.

The ram 12 is uniquely shaped in cross-section in order to properly cooperate with the rolls 72 of the die assembly 14 to form the workpiece W in accordance with the teachings of the instant invention. The ram includes a recess 80 on each opposing side of the ram body and intermediate the enlarged lateral end portions 82 thereof. In other words, the ram is somewhat I-shaped in cross-section and the planar surfaces 84 of the recesses 82 form the major workpiece contacting areas of the ram. The surfaces 84 intersect inner planar surfaces 86 on the end portions 82. The surfaces 84 on each forming side of the ram 12 extend to merge with each other at the curved nose end 85 of the ram 12. The lateral extent of the recess 80 on each side is slightly larger than the initial width of the workpiece W being treated in order to accommodate the workpiece and at the same time restrict outward flow of the metal in the workpiece during its reduction. The depth of the transverse surfaces 86 on each forming side of the ram 12 corresponds to the intended gauge to which the end portions of the bent workpiece are to be reduced by drawing. Thus, the workpiece W is relatively greater in gauge than the depth of a recess 80 on each side of the ram 12 in order to effect gauge reduction of the end portions of the bent workpiece as the ram 12 forces the bent workpiece W past the rolls 72 and in effect forces a drawing of metal backwards into and along recesses 80. In other words, the material of the workpiece flows longitudinally within the recesses 80 toward the rod end 38 of the ram 12 during treatment.

In order to properly center or orient the workpiece relative to the ram 12 and the die assembly 14 during the treatment thereof, the transverse spacing between the planar surfaces 88 at each lateral end portion of the ram 12 is set so as to substantially correspond to the spacing between the spaced rolls 72 of the die assembly 14. Thus, as the ram 12 advances through the die assembly with a workpiece W, the surfaces 88 on each forming side of the ram 12 tangentially contact the end portions of the as O- ciated roll 72 as shown in FIG. 4 and act to center the workpiece for attaining accurate gauge reduction and burnishing of the end portions S of the workpiece W. The apparatus 12 can be adjusted for different size workpieces or different gauge reduction for the same size workpiece by merely changing the size of the ram or adjusting the restriction between the rolls 72 of the die assembly 14 by use of different blocks 56 provided with different locations for the bearings of rolls 72.

A significant feature of the instant invention is that after the workpiece has been formed as aforedescribed and with a surface burnished by a roll 72, the nose portion N below the dotted line L as shown in FIG. 5 can be severed from the workpiece W" by appropriate severing equipment (not shown) whereby the severed end portions S" constitute a finished plate section of a predetermined gauge and length. These plate sections can be used ot meet the requirements for a metal plate used in a lithographic process in the printing industry. Although not heretofore mentioned, the nose portion N of the formed workpiece W substantially corresponds to the initial thickness of the workpiece W prior to the workpiece being bent and burnished and drawn as aforedescri'bed. After treatment of a workpiece by the apparatus of the instant application the doubled-over workpiece can be subjected to a stretcher leveling operation to obtain the desired flatness in each section of the plate. Thereafter the nose position of the workpiece is severed in the fashion noted in FIG. 5. Stretcher leveling of the folded-over workpiece further simplifies the overall production of the desired plate for use in the printing trade.

In practicing the invention the initial gauge of the plate or workpiece preferably should exceed the finished or desired gauge by about 20%. Thus, if a /2" final aluminum plate is desired, the initial plate can be approximately 9 10" thick having the chemical composition of 0.50% silicon, 0.30% iron, 0.10% copper, 1.0% manganese, 0.05% Zinc, 0.15% impurities and the remainder aluminum and being cold worked until exhibiting the characteristic of halfhardness. The chemical composition of the plate is designated according to the Aluminum Association as 3003 while the half-hardness is designated at H14. Thus, a plate 48 wide and 60 long and in thickness could be elongated and reduced and then stretcher leveled t provide two plate sections of approximately 48 in width, about 30" to 33" in length and of /a in thickness.

The reduced SOUS-Hi4 plate as to finish on the burnished surfaces indicated a root mean square reading in the range of 48 microinches according to a visual comparison with a surface roughness scale. Aluminum plate rolled through a rolling mill normally has a finish on their rolled surfaces with a root mean square reading in the range of l624 microinches. Thus, the reduced and burnished plate of 3003-Hl4 according to the teachings of the instant invention has a relatively brighter finish than the finish of aluminum plate reduced in a normal manner by a rolling mill.

An advantageous embodiment of the invention has been shown and described. It will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the spirit and scope thereof as set forth in the appended claims, wherein:

What is claimed is:

1. An apparatus for forming a length of metallic strip material into a U-shaped workpiece and then reducing the cross sectional thickness of a portion of the workpiece, the U-shaped workpiece consisting of two leg sections joined together 'by a nose portion, said apparatus comprising the combination of an advanceable ram and a die assembly disposed in cooperative relation with said ram, said die assembly having an opening therethrough and a pair of workpiece engaging rolls rotatably mounted in bearings fixed in said die assembly and disposed on opposite sides of the opening, said ram being provided with a channel shaped recessed pocket means for receiving at least one leg section of the workpiece and for restraining the lateral flow of the metal of the workpiece of the said one leg section during advancement of the ram and the workpiece through the opening in the die assembly and past said rolls, at least one back-up roll rotatably mounted in said die assembly in spaced relation to the opening thereof and in surface-to-surface contact with one of said workpiece engaging rolls and means for advancing said ram along with the workpiece through the opening of said die assembly and past said workpiece engaging rolls in such fashion so as to cause engagement of said ram and the workpiece with said workpiece engaging rolls while at least the said one leg section of the workpiece is disposed within the pocket means of said ram and with said back-up roll acting to maintain said one workpiece engaging roll in full rolling engagement with said ram and at least the one leg section of the workpiece disposed within the channel shaped pocket means of said ram.

2. An apparatus as set forth in claim 1 wherein said ram is provided with recessed pocket means on opposing sides thereof and wherein another backup roll is rotatably mounted in said die assembly in spaced relation to the opening thereof but in surface-to-surface contact with the other one of said workpiece engaging rolls.

3. An apparatus as set forth is claim 1 wherein the forward portion of the ram is provided with a rounded nose portion.

4. An apparatus as set forth in claim 2 wherein the forward portion of the ram is provided with a rounded nose portion and said channel shaped recessed pocket means includes a fiat planar surface which merges smoothly with the rounded nose portion of the ram.

5. A method for forming metallic plate sections such as aluminum of a selected gauge and surface finish from a length of plate initially of larger gauge, comprising the steps of bending said plate into a substantially U-shaped workpiece having leg sections joined together by a nose portion, working both leg sections of the U-shaped workpiece in a direction from the nose portion thereof to the ends of the leg sections to effect a reduction in thickness of both of said leg sections while restraining lateral flow of metal therein and severing the leg sections of the workpiece from each other adjacent the point where they are joined together.

6. The method as set forth in claim 5 including the step of stretcher leveling the workpiece prior to severing the leg sections thereof from each other.

7. A method for forming a metallic plate section such as aluminum of a selected gauge and surface finish from a lengh of plate initially of larger gauge, comprising the steps of bending said plate into a substantially U-shaped workpiece having leg sections joined together by a nose portion, working at least one of said leg sections of the U-shaped workpiece in a direction from the nose portion thereof to the end of the said one leg section to effect a reduction in thickness of said one leg section while restraining lateral flow of metal therein and thereafter severing the leg sections of the workpiece from each other adjacent the point where they are joined together.

References Cited UNITED STATES PATENTS 2,613,718 10/1952 Vaughnetal 72-338 2,669,891 2/1954 Ware 72 1s4 1,573,503 2/1926 Rifner 72-452 2,274,828 3/1942 FlIlZel 72206 2,339,855 1/1944 Hodiletal 72- 213 2,568,373 9/1951 Sweet 72 213 2,908,315 10/1959 'Hellig 72-206 3,209,576 10/1965 Giordono 72 3s9 3,271,990 9/1966 Mitchell 72389 9 RICHARD J. HERBST, Primary Examiner A. RUDERMAN, Assistant Examiner US. Cl. X.R. 72-2l3, 352, 389 

